Coordination is the selection and setting of protective devices in order to isolate only the portion of the system where the abnormality occurs. Coordination is a basic ingredient of a well-designed electrical distribution protection system and is compulsory in certain health care and continuous process industrial power systems. The system protection is one of the most initial and essential features of an electrical network and should be considered concurrently with all other essential features. Too often system protection is considered after all other design features have been determined and the basic system design has been established. Such an approach may result in an unsatisfactory system that cannot be adequately protected, except by a disproportionately high expenditure. The designer should thoroughly examine the question of system protection at each stage of planning and incorporate into the final system a fully integrated protection plan that is capable of, and is flexible enough, to grow with the system. The isolation of short circuits and overloads requires the application of protective equipment that senses when an abnormal current flow exists and then removes the affected portion from the system. The three primary protective equipment components used in the isolation of short circuits and overloads are fuses, circuit breakers and protective relays.